Low profile catheter assemblies and associated systems and methods

ABSTRACT

Catheters including elements configured to deliver energy to nerves at or near a treatment location within a body lumen. A treatment assembly is transformable between a low-profile delivery configuration wherein a pair of electrodes are in a staggered arrangement relative to each other along the longitudinal axis, and an expanded deployed configuration wherein the pair of electrodes is aligned along an electrode axis that is orthogonal relative to the longitudinal axis.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 14/208,769, filed Mar. 13, 2014 (published as U.S. PatentPublication US 2015/0257825 A1 on Sep. 17, 2015).

TECHNICAL FIELD

The present technology is related to catheters. In particular, at leastsome embodiments are related to low profile neuromodulation cathetersincluding energy delivery elements configured to deliver energy tonerves at or near a treatment location within a body lumen.

BACKGROUND

The sympathetic nervous system (SNS) is a primarily involuntary bodilycontrol system typically associated with stress responses. Fibers of theSNS extend through tissue in almost every organ system of the human bodyand can affect characteristics such as pupil diameter, gut motility, andurinary output. Such regulation can have adaptive utility in maintaininghomeostasis or in preparing the body for rapid response to environmentalfactors. Chronic activation of the SNS, however, is a common maladaptiveresponse that can drive the progression of many disease states.Excessive activation of the renal SNS, in particular, has beenidentified experimentally and in humans as a likely contributor to thecomplex pathophysiologies of hypertension, states of volume overload(e.g., heart failure), and progressive renal disease.

Sympathetic nerves of the kidneys terminate in the renal blood vessels,the juxtaglomerular apparatus, and the renal tubules, among otherstructures. Stimulation of the renal sympathetic nerves can cause, forexample, increased renin release, increased sodium reabsorption, andreduced renal blood flow. These and other neural-regulated components ofrenal function are considerably stimulated in disease statescharacterized by heightened sympathetic tone. For example, reduced renalblood flow and glomerular filtration rate as a result of renalsympathetic efferent stimulation is likely a cornerstone of the loss ofrenal function in cardio-renal syndrome (i.e., renal dysfunction as aprogressive complication of chronic heart failure). Pharmacologicstrategies to thwart the consequences of renal sympathetic stimulationinclude centrally-acting sympatholytic drugs, beta blockers (e.g., toreduce renin release), angiotensin-converting enzyme inhibitors andreceptor blockers (e.g., to block the action of angiotensin II andaldosterone activation consequent to renin release), and diuretics(e.g., to counter renal sympathetic mediated sodium and waterretention). These pharmacologic strategies, however, have significantlimitations including limited efficacy, compliance issues, side effects,and others.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present technology can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale. Instead, emphasis is placed on illustratingclearly the principles of the present technology. For ease of reference,throughout this disclosure identical reference numbers may be used toidentify identical or at least generally similar or analogous componentsor features.

FIG. 1 is a perspective view of a system including a catheter, console,and cable configured in accordance with an embodiment of the presenttechnology. The catheter includes an elongated shaft and a treatmentassembly carried by the shaft.

FIGS. 2A-2C are enlarged views of the treatment assembly of FIG. 1. InFIG. 2A, the treatment assembly is shown in a low-profile deliveryconfiguration. In FIGS. 2B and 2C, the treatment assembly is shown in anexpanded deployed configuration.

FIGS. 2D and 2E are schematic views of contact regions defined by thetreatment assembly of FIG. 1 when the treatment assembly is deployedwithin a body lumen in accordance with an embodiment of the presenttechnology.

FIGS. 3A-3C are enlarged views of a treatment assembly of a catheterconfigured in accordance with another embodiment of the presenttechnology. In FIG. 3A, the treatment assembly is shown in a low-profiledelivery configuration. In FIGS. 3B and 3C, the treatment assembly isshown in an expanded deployed configuration.

FIG. 4 is a partially schematic side cross-sectional view of a handleassembly configured in accordance with an embodiment of the presenttechnology.

FIGS. 5A and 5B are partially schematic side views of a treatmentassembly configured in accordance with yet another embodiment of thepresent technology.

FIGS. 6A-6C are enlarged anatomical side views of the treatment assemblyshown in FIG. 1A and associated components located at a treatmentlocation within a renal artery of a human patient. In FIG. 6A, adelivery sheath is inserted into a renal artery. In FIG. 6B, thetreatment assembly is shown extended from the sheath in an intermediatestate. In FIG. 6C, the treatment assembly is shown in the deployedstate.

DETAILED DESCRIPTION

The present technology is related to catheters, such as low profileneuromodulation catheters with independent expansion members carryingenergy delivery elements configured to deliver energy to nerves at ornear a treatment location within a body lumen. Embodiments of thepresent technology, for example, are directed to catheters having energydelivery elements arranged in a staggered or misaligned arrangement whenthe catheter is in a low-profile delivery configuration. In this way,the energy delivery elements are not overlapping when the catheter is ina low-profile delivery configuration, which is expected to reduce theoverall profile of the catheter. Further, when the energy deliveryelements are at a desired treatment site within the patient, thetreatment assembly is transformable to an expanded, deployed arrangementsuch that the energy delivery elements are aligned relative to eachother (e.g., lie in a plane that is orthogonal relative to alongitudinal axis of the catheter) and are positioned to produce adesired ablation pattern in target tissue.

Neuromodulation catheters configured in accordance with embodiments ofthe present technology can include, for example, an elongated tubularshaft extending along a longitudinal axis. The elongated shaft includesa proximal portion and a distal portion. The catheter can also include atreatment assembly at the distal portion of the shaft and configured tobe located at a target location within a blood vessel of a humanpatient. The treatment assembly includes a pair of electrodes. Thetreatment assembly is transformable between (a) a low-profile deliveryconfiguration wherein the pair of electrodes are in a staggeredarrangement relative to each other along the longitudinal axis, and (b)an expanded deployed configuration wherein the pair of electrodes arealigned along an electrode axis that is orthogonal relative to thelongitudinal axis.

Specific details of several embodiments of the present technology aredescribed herein with reference to FIGS. 1-6C. Although many of theembodiments are described herein with respect to devices, systems, andmethods for percutaneous intravascular renal neuromodulation, otherclinical applications and other embodiments in addition to thosedescribed herein are within the scope of the present technology. Forexample, at least some embodiments may be useful for neuromodulationwithin a body lumen other than a blood vessel, for non-renalneuromodulation, and/or for use in therapies other than neuromodulation.It should be noted that other embodiments in addition to those disclosedherein are within the scope of the present technology. Furthermore,embodiments of the present technology can have different configurationsand components, and may be used for procedures different from thosedisclosed herein. Moreover, a person of ordinary skill in the art willunderstand that embodiments of the present technology can haveconfigurations, components, and/or procedures in addition to thosedisclosed herein and that these and other embodiments can be withoutseveral of the configurations, components, and/or procedures disclosedherein without deviating from the present technology.

As used herein, the terms “distal” and “proximal” define a position ordirection with respect to a clinician or a clinician's control device(e.g., a handle of a catheter). The terms, “distal” and “distally” referto a position distant from or in a direction away from a clinician or aclinician's control device. The terms “proximal” and “proximally” referto a position near or in a direction toward a clinician or a clinician'scontrol device. The headings provided herein are for convenience onlyand should not be construed as limiting the subject matter disclosed.

Selected Examples of Neuromodulation Catheters and Related Devices

FIG. 1 is a perspective view of a system 100 (e.g., a neuromodulationsystem) configured in accordance with an embodiment of the presenttechnology. The system 100 can include a catheter 102 (e.g., aneuromodulation catheter), a console 104, and a cable 106 extendingtherebetween. The catheter 102 can include an elongate shaft 108 havinga proximal end portion 110 and a distal end portion 112. The catheter102 can further include a handle 114 and a treatment or therapeuticassembly 116 operably connected to the shaft 108 via, respectively, theproximal and distal end portions 110, 112 of the shaft 108. The shaft108 can be configured to intravascularly locate the treatment assembly116 at a treatment location within a body lumen, such as a suitableblood vessel, duct, airway, or other naturally occurring lumen withinthe human body. The treatment assembly 116 can be configured to provideor support therapy (e.g., a neuromodulation treatment) at the treatmentlocation.

The treatment assembly 116 may be configured to be radially constrainedand slidably disposed within a delivery sheath (not shown) while thecatheter 102 is being deployed within a body lumen. The outside diameterof the sheath can be 5, 6, or 7 French or another suitable size. Asanother example, the catheter 102 can be steerable or non-steerable andconfigured for deployment without a guide wire. The catheter 102 canalso be configured for deployment via a guide catheter (not shown) withor without the use of a delivery sheath or a guide wire.

The console 104 can be configured to control, monitor, supply energy,and/or otherwise support operation of the catheter 102. Alternatively,the catheter 102 can be self-contained or otherwise configured foroperation without connection to a console 104. When present, the console104 can be configured to generate a selected form and/or magnitude ofenergy for delivery to tissue at or near a treatment location via thetreatment assembly 116. The console 104 can have differentconfigurations depending on the treatment modality of the catheter 102.When the catheter 102 is configured for electrode-based,heat-element-based, or transducer-based treatment, for example, theconsole 104 can include an energy generator (not shown) configured togenerate radio frequency (RF) energy (e.g., monopolar and/or bipolar RFenergy), pulsed electrical energy, microwave energy, ultrasound energy(e.g., intravascularly delivered ultrasound energy, high-intensityfocused ultrasound energy), direct heat, electromagnetic radiation(e.g., infrared, visible, and/or gamma radiation), and/or anothersuitable type of energy. Similarly, when the catheter 102 is configuredfor chemical-based treatment (e.g., drug infusion), the console 104 caninclude a chemical reservoir (not shown) and can be configured to supplythe catheter 102 with one or more chemicals.

In some embodiments, the system 100 includes a control device 118 alongthe cable 106. The control device 118 can be configured to initiate,terminate, and/or adjust operation of one or more components of thecatheter 102 directly and/or via the console 104. In other embodiments,the control device 118 can be absent or can have another suitablelocation, such as within the handle 114. The console 104 can beconfigured to execute an automated control algorithm 120 and/or toreceive control instructions from an operator. Furthermore, the console104 can be configured to provide information to an operator before,during, and/or after a treatment procedure via an evaluation/feedbackalgorithm 122.

FIGS. 2A-2C are enlarged views of the treatment assembly 116. Morespecifically, in FIG. 2A, the treatment assembly 116 is shown in alow-profile delivery configuration. In FIGS. 2B and 2C, the treatmentassembly 116 is shown in an expanded deployed configuration. Referringfirst to FIG. 2A, the treatment assembly 116 can include a first strutor expansion member 130 and a second strut or expansion member 140. Thefirst strut 130 is arranged about a longitudinal axis A of the shaft 108along a first curved path, and the second strut 140 is arranged aboutthe longitudinal axis A along a second curved path offset from the firstcurved path. The first and second struts 130 and 140 may be composed ofmetal (e.g., titanium nickel alloy commonly known as nitinol or springtempered stainless steel). In other embodiments, the first and secondstruts 130 and 140 may be composed of other suitable materials. Further,in still other embodiments (such as those described below with referenceto FIG. 3A-3C), the treatment assembly 116 may include more than twostruts or expansion members.

The first and second struts 130 and 140 can be movably (e.g., slidably)connected to the shaft 108. For example, the first strut 130 can includea first fixed end portion 132 coupled to the shaft 108 and a first freeend portion 134 slidably engaged with the shaft 108 at a location distalof the first fixed end portion 132. In the illustrated embodiment, thefirst free end portion 134 is slidably disposed within a first channelor groove 150 of the shaft 108. In other embodiments, however, the firstfree end portion 134 may be slidably engaged with the shaft 108 viaanother arrangement. The second strut 140 includes a second fixed endportion 142 coupled to the shaft 108 and a second free end portion 144slidably engaged with the shaft 108 at a location proximal of the secondfixed end portion 142. In the illustrated embodiment, for example, thesecond free end portion 144 is slidably disposed within a second channelor groove 152. In the present arrangement, the first fixed end portion132 is adjacent to the second free end portion 144 along the shaft 108,and the first free end portion 134 is adjacent the second fixed endportion 142. In other embodiments, however, the first and secondfixed/free ends 132/134/142/144 may have a different arrangementrelative to each other along the shaft 108. As described in greaterdetail below, the first and second struts 130 and 140 are configured toexpand radially outward from the shaft 108 in conjunction with thecorresponding free end portions 134 and 144 slidably moving in oppositedirections along the shaft 108.

The treatment assembly 116 further comprises a plurality of energydelivery elements or electrodes 154 (identified individually as firstthrough fourth electrodes 154 a-154 d, respectively, and referred tocollectively as electrodes 154). Although the electrodes 154 in theillustrated embodiment are shown as ring or band electrodes, it will beappreciated that the electrodes 154 may have variousconfigurations/shapes (e.g., electrodes with generally flat/planarsurfaces, electrodes with crescent-shaped cross-sectional profiles,etc.). In the illustrated embodiment, the electrodes 154 are arranged inpairs, including a first pair (comprising the first and secondelectrodes 154 a and 154 b) and a second pair (comprising the third andfourth electrodes 154 c and 154 d). When the treatment assembly 116 isin the low-profile delivery configuration such as shown in FIG. 2A, theelectrodes 154 are in a staggered arrangement relative to each otheralong the longitudinal axis A. As described in greater detail below withreference to FIGS. 2B and 2C, when the treatment assembly 116 istransformed to the expanded deployed configuration, the pairs ofelectrodes (the first pair 154 a/154 b and the second pair 154 c/154 d)are aligned along electrode axes that are orthogonal relative to thelongitudinal axis A. In other embodiments, the treatment assembly 116may have a different number of electrodes 154 and/or the electrodes 154may have different arrangements/positions relative to each other on thetreatment assembly 116. In still further embodiments, the treatmentassembly 116 can include energy delivery elements other than electrodes,such as devices suitable for providing other energy-based orchemical-based treatment modalities.

A first control member 160 (shown schematically as a broken line) isoperably coupled between the first free end portion 134 of the firststrut 130 and the handle 114 (FIG. 1) at the proximal end portion 110(FIG. 1) of the shaft 108. A second control member 162 (also shownschematically as a broken line) is operably coupled between the secondfree end portion 144 of the second strut 140 and the handle 114 (FIG.1). In one embodiment, for example, the first control member 160comprises a pull wire and the second control member 162 comprises a pushwire. In other embodiments, however, the first control member 160 and/orsecond control member 162 may have a different configuration. The firstand second control members 160 and 162 may be manually actuated by oneor more operators (not shown) such as levers or knobs to transform thetreatment assembly 116 between the delivery configuration (as shown inFIG. 2A) and the deployed configuration.

FIGS. 2B and 2C, for example, are an enlarged side view and an enlargedperspective view, respectively, of the treatment assembly 116 in thedeployed configuration. As best seen in FIG. 2B, slidably moving thefirst free end portion 134 of strut 130 along slot 150 in a proximaldirection (as shown by arrow P) via first control member 160 radiallyexpands the first strut 130. Likewise, slidably moving the second freeend portion 144 of strut 140 along slot 152 in a distal direction (asshown by arrow D) via second control member 162 radially expands thesecond strut 140. As mentioned above, for example, in one embodiment thefirst control member 160 comprises a pull wire adapted to bepushed/pulled by the operator (not shown) to slidably move the firstfree end portion 134 along slot 150 while the first fixed end portion132 remains stationary, and the second control member 162 comprises apush wire adapted to be pulled/pushed by the operator to slidably movethe second free end portion 144 along slot 152 while the second fixedend portion 142 remains stationary.

As best seen in FIG. 2C, when the treatment assembly 116 is in thedeployed configuration, the first pair of electrodes 154 a/154 b aregenerally aligned along a first electrode axis E₁ orthogonal ortransverse to the catheter longitudinal axis A, and the second pair ofelectrodes 154 c/154 d are generally aligned along a second electrodeaxis E₂ orthogonal or transverse to the catheter longitudinal axis A. Inthe illustrated embodiment, the first electrode axis E₁ and the secondelectrode axis E₂ are spaced apart from each other along thelongitudinal axis A and angularly offset by approximately 90 degrees. Inother embodiments, however, the first electrode axis E₁ and the secondelectrode axis E₂ may have a different arrangement relative to eachother.

The curved first and second struts 130/140 each have a selectedtwist/radial sweep such that, when they are in the deployedconfiguration, the electrodes 154 a-d carried by corresponding struts130/140 are urged into apposition with an inner wall of a body lumen atcorresponding contact regions. Referring to FIGS. 2D and 2E, forexample, the contact regions of the electrodes 154 a-d (shown withoutthe struts 130/140 or shaft 108 for purposes of illustration) can belongitudinally and circumferentially spaced apart along a body lumen Lsuch that the treatment assembly 116 (FIG. 2C) can be used to form adesirable treatment profile.

FIGS. 3A-3C are enlarged views of a treatment assembly 216 configured inaccordance with another embodiment of the present technology. Thetreatment assembly 216 may be used with the catheter 102 (FIG. 1), ormay be used with other suitable catheters. In FIG. 3A, the treatmentassembly is shown in a low-profile delivery configuration. In FIGS. 3Band 3C, the treatment assembly is shown in an expanded deployedconfiguration. Referring first to FIG. 3A, the treatment assembly 216differs from the treatment assembly 116 described above in that, ratherthan having two curved/arched struts 130/140, the treatment assembly 216includes four struts or members 230 (identified individually as firstthrough fourth struts 230 a-230 d, respectively, and referred tocollectively as struts 230). As described in greater detail below withreference to FIGS. 3B and 3C, the struts 230 are arranged to define abasket-like assembly.

The first strut 230 a includes a first fixed end portion 232 a coupledto the shaft 108 and a first free end portion 234 a slidably engagedwith the shaft 108 at a location distal of the first fixed end portion232 a. The second strut 230 b includes a second fixed end portion 232 bcoupled to the shaft 108 and a second free end portion 234 b slidablyengaged with the shaft 108 at a location proximal of the second fixedend portion 232 b. The third strut 230 c includes a third fixed endportion 232 c coupled to the shaft 108 and a third free end portion 234c slidably engaged with the shaft 108 at a location distal of the thirdfixed end portion 232 c. The fourth strut 230 d includes a fourth fixedend portion 232 d coupled to the shaft 108 and a fourth free end portion234 d slidably engaged with the shaft 108 at a location proximal of thefourth fixed end portion 232 d.

The first and third fixed end/free end portions 232 a/232 c and 234a/234 c, respectively, may be proximate each other along the shaft 108,and the second and fourth fixed end/free end portions 232 b/232 d and234 b/234 d, respectively, may be proximate each other along the shaft108. In some embodiments, for example, (a) the first and third fixedend/free end portions 232 a/232 c and 234 a/234 c may be aligned alongthe longitudinal axis A in both delivery and deployed configurations,and (b) the second and fourth fixed end/free end portions 232 b/232 dand 234 b/234 d may be aligned along the longitudinal axis A in bothdelivery and deployed configurations. In other embodiments, however, thefree end portions 232 a-d and/or fixed end portions 234 a-d of thestruts 230 may have a different arrangement relative to each other.

Each strut 230 is configured to carry one or more energy deliveryelements or electrodes 254. In the illustrated embodiment, for example,the first through fourth struts 230 a-d each carry a single electrode254 (identified individually as first through fourth electrodes 254a-254 d, respectively, and referred to collectively as electrodes 254).In other embodiments, however, the struts 230 may include a differentnumber of electrodes 254 and/or the electrodes 254 may have a differentarrangement relative to each other. In still further embodiments, and asnoted previously with reference to treatment assembly 116, the treatmentassembly 216 may include energy delivery elements other than electrodes,such as devices suitable for providing other energy-based orchemical-based treatment modalities.

FIGS. 3B and 3C are an enlarged side view and an enlarged perspectiveview, respectively, of the treatment assembly 216 in the expandeddeployed configuration. Referring first to FIG. 3B, actuating (e.g.,slidably moving) the first and third free end portions 234 a/234 c ofthe first and third struts 230 a/230 c, respectively, along slot 250 ina proximal direction (as shown by arrow P) via a first control member260 transforms the first and third struts 230 a/230 c from theconstrained, low-profile delivery configuration of FIG. 3A to theexpanded, deployed configuration of FIGS. 3B/3C. In one embodiment, forexample, the first control member 260 comprises a pull wire operablycoupled between (a) the first and third free end portions 234 a/234 cand (b) the handle 114 (FIG. 1) at the proximal portion 110 of the shaft108. The first control member 260 is configured to be pushed/pulled byan operator via manipulation at the handle 114 (FIG. 1) to slidably movethe first and third free end portions 234 a/234 c. Further detailsregarding the handle 114 are described below with reference to FIG. 4.

Actuating (e.g., slidably moving) the second and fourth free endportions 234 b/234 d of the second and fourth struts 230 b/230 d,respectively, along slot 252 in a distal direction (as shown by arrow D)via a second control member 262 transforms the second and fourth struts230 b/230 d from the constrained, low-profile delivery configuration ofFIG. 3A to the deployed configuration of FIGS. 3B/3C. In one embodiment,for example, the second control member 262 comprises a push wireoperably coupled between (a) the second and fourth free end portions 234b/234 d and (b) the handle 114 (FIG. 1). Like the first control member260 described above, the second control member 262 is configured to bepushed/pulled by an operator via manipulation at the handle 114 (FIG. 1)to slidably move the second and fourth free end portions 234 b/234 d.

As best seen in FIG. 3C and as mentioned previously, the treatmentassembly 216 comprises a basket-like assembly in its deployedconfiguration. Further, in this configuration, a first pair ofelectrodes (e.g., electrodes 254 a/254 b) is generally aligned along athird electrode axis E₃ orthogonal or transverse to the catheterlongitudinal axis A, and a second pair of electrodes (e.g., electrodes254 c/254 d) is generally aligned along a fourth electrode axis E₄orthogonal or transverse to the longitudinal axis A. In the illustratedembodiment, the third electrode axis E₃ is spaced apart from the fourthelectrode axis E₄ along the longitudinal axis and angularly offset fromthe fourth electrode axis E₄ by approximately 90 degrees. In otherembodiments, however, the third electrode axis E₃ and the fourthelectrode axis E₄ may have a different arrangement relative to eachother.

As mentioned above, the treatment assemblies 116/216 may be transformedbetween the delivery and deployed states via manipulation of the handle114 by an operator or clinician. FIG. 4, for example, is a partiallyschematic side cross-sectional view of the handle 114 configured inaccordance with an embodiment of the present technology. The illustratedhandle 114 may be utilized with the treatment assemblies 116/216described above with reference to FIGS. 2A-3C, or other suitabletreatment assemblies.

The handle 114 comprises a housing 302 and an actuation assembly ormechanism 310 carried by the housing 302. The actuation assembly 310 caninclude a pinion gear 312 mated with opposing first and second racks314/315. The first control member 160 (or 260) extends through the shaft108 and operably couples to first rack 315. The second control member162 (or 262) extends through the shaft 108 and operably couples tosecond rack 314. In one embodiment, for example, the first rack 315 iscoupled to a button or engagement member 316.

In operation, when an operator pulls the button 316 proximally (as shownby direction 1 of the arrow), the first rack 315 pulls the first controlmember 160 proximally. Such movement results in simultaneous rotation ofthe gear 312, thereby moving the second rack 314 in the oppositedirection (distally as shown by direction 2 of the arrow). The distalmovement of the rack 314 also pushes the second control member 162 inthe distal direction. In one embodiment, this sequence deploys thetreatment assembly 116 (or 216) from the low-profile deliveryconfiguration to an expanded deployed configuration. Likewise, in thisembodiment, when the operator pushes the button 316 distally (in thedirection 2 of the arrow), the above-described sequence is reversed totransform the treatment assembly 116 (or 216) from the deployedconfiguration to the low-profile delivery configuration. In otherembodiments, however, the actuation assembly 310 of the handle 114 mayhave a different arrangement and/or include different features toactuate the treatment assembly 116/216. For example, in someembodiments, the handle 114 may include separate mechanisms toindependently actuate the control members 160 and 162 rather than anintegrated actuation assembly 310 that simultaneously controls bothcontrol members 160 and 162.

FIGS. 5A and 5B are partially schematic side views of a treatmentassembly 416 configured in accordance with yet another embodiment of thepresent technology. The treatment assembly 416 may be used with thecatheter 102 (FIG. 1) or other suitable catheters. In FIG. 5A, thetreatment assembly 416 is shown in a low-profile delivery configuration,while in FIG. 5B the treatment assembly is shown in an expanded deployedconfiguration. Referring to FIGS. 5A and 5B together, the treatmentassembly 416 differs from the treatment assemblies 116 and 216 describedabove in that, rather than having two or more struts that areindependently actuated via independent, discrete control members, thetreatment assembly 416 includes a single control member 460 (e.g., apullrod) slidably movable within a lumen of the shaft 108 and connectedto two or more strut assemblies of the treatment assembly 416. Actuationof the single control member 460 transforms the multiple strutassemblies of the treatment assembly 416 between delivery and deployedconfigurations.

In the illustrated embodiment, the treatment assembly 416 includes afirst strut assembly 430 and a second strut assembly 440. The firststrut assembly 430, for example, includes a first leg 431 a, a secondleg 431 b, and a first energy delivery element or electrode 454 abetween the first and second legs 431 a and 431 b. In the illustratedembodiment, the first leg 431 a has a first length and the second leg431 b has a second length greater than the first length. The secondstrut assembly 440 also includes a third leg 441 a, a fourth leg 441 b,and a second energy delivery element or electrode 454 b therebetween.The third and fourth legs 441 a/441 b of the second strut assembly 440,however have the opposite arrangement from that of the first strutassembly 430. That is, the third leg 441 a of the second strut assembly440 includes a first length and the fourth leg 441 b has a second lengthless than the first length. In other embodiments, however, the first andthird legs 431 a, 441 a and/or the second and fourth legs 431 b, 441 bmay have a different arrangement relative to each other.

The first leg 431 a includes a fixed end portion 432 fixedly attached toan outer surface of the shaft 108, e.g by a living hinge. The second leg431 b includes a free end portion 434 coupled to a control member 460slidably movable within the shaft 108. The third leg 441 a of the secondstrut assembly 440 includes a fixed end portion 442 fixedly attached tothe outer surface of the shaft 108 proximal of the fixed end portion 432of the first leg 431 a. The fourth leg 441 b includes a free end portion444 coupled to the control member 460 proximal of the free end portion434 of the second leg 431 b.

As best seen in FIG. 5A of the illustrated embodiment, when thetreatment assembly 416 is in the low-profile delivery configuration, thefirst leg 431 a and/or the second leg 431 b of the first strut assembly430 are parallel or generally parallel with the longitudinal axis A.Likewise, the third leg 441 a and/or the fourth leg 441 b of the secondstrut assembly 440 are parallel or generally parallel with thelongitudinal axis A. In other embodiments, however, the individual legs431 a, 431 b, 441 a, 441 b may have a different arrangement relative thelongitudinal axis A and/or each other when the treatment assembly 416 isin the delivery configuration.

In the delivery configuration, the first and second electrodes 454 a and454 b are positioned to be received in axially staggered pockets oropenings 456 in the shaft 108. This recessed arrangement for theelectrodes is expected to further reduce the overall profile of thetreatment assembly 416. In other embodiments, however, the shaft 108 maynot include openings 456 and the electrodes 454 a and 454 b may engagean outermost surface of the shaft 108 in the delivery configuration.

Proximal movement of the control member 460 (as shown by the arrow P inFIG. 5B) transforms the first and second strut assemblies 430 and 440 ofthe treatment assembly 416 from the delivery configuration (FIG. 5A) tothe deployed configuration (FIG. 5B). During this transformation, thefirst and second electrodes 454 a and 454 b pivot or swing outwardlyaway from the shaft 108 along separate arcs until the electrodes 454 aand 454 b are aligned with each other along an electrode axis E₅generally orthogonal or transverse to the catheter longitudinal axis A.As also seen in FIG. 5B, the legs of comparable length (i.e., the firstand fourth legs 431 a and 441 b; the second and third legs 431 b and 441a) remain generally parallel to each other during actuation.

In the deployed configuration of FIG. 5B, the first leg 431 a and secondleg 431 b of the first strut assembly 430 together with the longitudinalaxis A define a generally triangular deployed shape. Similarly, thethird leg 441 a and fourth leg 441 b of the second strut assembly 440 inconjunction with the longitudinal axis A define a generally triangulardeployed shape. In other embodiments, however, the leg geometry canvary. For example, varying the length of one or more of the legs (e.g.,the proximal fixed legs—first leg 431 a and third leg 441 a) can varythe resulting offset distance of the electrodes 454 a and 454 b from thelongitudinal axis A when the treatment assembly 416 is in the deployedconfiguration. It will also be appreciated that although only two strutassemblies 430 and 440 are shown, the treatment assembly 416 may includeadditional strut assemblies. As an example, in one embodiment thetreatment assembly 416 may include another strut assembly operablycoupled to the control member 460 and offset (e.g., 90 degrees) aboutthe shaft 108 from strut assemblies 430 and 440.

FIGS. 6A-6C are enlarged anatomical side views of the treatment assembly116 shown in FIG. 1 and associated components being used for renalneuromodulation at a treatment site within a renal artery 500 thatextends between an aorta 502 and a kidney 504 in a human patient. Thetreatment assembly 116 can also be used for other purposes and attreatment locations within other suitable body lumens. To locate thetreatment assembly 116 at the treatment location, the catheter 102 canbe advanced toward the treatment location while the treatment assembly116 is radially constrained in a low-profile delivery state within adelivery sheath 506. In FIG. 6A, the treatment assembly 116 is in thedelivery state hidden within the delivery sheath 506. It will beunderstood by persons familiar with the field of catheterization thatcatheter 102 and sheath 506 would typically be guided, simultaneously orseparately, from a vascular puncture site to renal artery 500 using aguiding catheter and/or a medical guidewire, both of which are omittedfrom FIGS. 6A-6C for simplicity of illustration. In one embodiment, thetreatment assembly 116 is configured to fit within a delivery sheath 506and/or guiding catheter having a 6 F outer diameter.

In FIG. 6B, the treatment assembly 116 is shown in an intermediate stateas it transitions from the delivery state to a deployed state. Sheath506 is shown as having been withdrawn from renal artery 500 sufficientlyto expose treatment assembly 116, which remains radially constrained itits delivery configuration. In FIG. 6C, the treatment assembly 116 isshown in the deployed state. As described previously, deploying thetreatment assembly 116 can include independently radially expandingstruts 130/140 of the treatment assembly 116 by (a) slidably moving thefree end portion 134 of strut 130 in one direction (e.g., the proximaldirection) via the first control member 160 (FIG. 2B) that extendscompletely through the shaft 108 from the handle (not shown) to thetreatment assembly 116, and (b) slidably moving the free end portion 144of strut 140 in the opposite direction (e.g., the distal direction) viathe second control member 162 (FIG. 2B) that also extends from thehandle to the treatment assembly 116. As further noted above, struts130/140 have a preselected twist/radial sweep such that, when thetreatment assembly 116 is in the expanded deployed configuration,electrodes 154 are in apposition with an inner surface 508 of a wall 510of the renal artery 500. After treatment assembly 116 is deployed at thetreatment location, electrodes 154 can be energized to modulate one ormore nerves at or near the treatment location.

Renal Neuromodulation

Catheters configured in accordance with at least some embodiments of thepresent technology can be well suited (e.g., with respect to sizing,flexibility, operational characteristics, and/or other attributes) forperforming renal neuromodulation in human patients. Renalneuromodulation is the partial or complete incapacitation or othereffective disruption of nerves of the kidneys (e.g., nerves terminatingin the kidneys or in structures closely associated with the kidneys). Inparticular, renal neuromodulation can include inhibiting, reducing,and/or blocking neural communication along neural fibers (e.g., efferentand/or afferent neural fibers) of the kidneys. Such incapacitation canbe long-term (e.g., permanent or for periods of months, years, ordecades) or short-term (e.g., for periods of minutes, hours, days, orweeks). Renal neuromodulation is expected to contribute to the systemicreduction of sympathetic tone or drive and/or to benefit at least somespecific organs and/or other bodily structures innervated by sympatheticnerves. Accordingly, renal neuromodulation is expected to be useful intreating clinical conditions associated with systemic sympatheticoveractivity or hyperactivity, particularly conditions associated withcentral sympathetic overstimulation. For example, renal neuromodulationis expected to efficaciously treat hypertension, heart failure, acutemyocardial infarction, metabolic syndrome, insulin resistance, diabetes,left ventricular hypertrophy, chronic and end stage renal disease,inappropriate fluid retention in heart failure, cardio-renal syndrome,polycystic kidney disease, polycystic ovary syndrome, osteoporosis,erectile dysfunction, and sudden death, among other conditions.

Renal neuromodulation can be electrically-induced, thermally-induced,chemically-induced, or induced in another suitable manner or combinationof manners at one or more suitable treatment locations during atreatment procedure. The treatment location can be within or otherwiseproximate to a renal lumen (e.g., a renal artery, a ureter, a renalpelvis, a major renal calyx, a minor renal calyx, or another suitablestructure), and the treated tissue can include tissue at least proximateto a wall of the renal lumen. For example, with regard to a renalartery, a treatment procedure can include modulating nerves in the renalplexus, which lay intimately within or adjacent to the adventitia of therenal artery. Various suitable modifications can be made to thecatheters described above to accommodate different treatment modalities.For example, the electrodes 154 (FIGS. 2A-2C) can be replaced withtransducers to facilitate transducer-based treatment modalities. Asanother example, the electrodes 154 can be replaced with drug-deliveryelements (e.g., needles) to facilitate chemical-based treatmentmodalities. Other suitable modifications are also possible.

Renal neuromodulation can include an electrode-based or treatmentmodality alone or in combination with another treatment modality.Electrode-based or transducer-based treatment can include deliveringelectricity and/or another form of energy to tissue at or near atreatment location to stimulate and/or heat the tissue in a manner thatmodulates neural function. For example, sufficiently stimulating and/orheating at least a portion of a sympathetic renal nerve can slow orpotentially block conduction of neural signals to produce a prolonged orpermanent reduction in renal sympathetic activity. A variety of suitabletypes of energy can be used to stimulate and/or heat tissue at or near atreatment location. For example, neuromodulation in accordance withembodiments of the present technology can include delivering RF energy,pulsed electrical energy, microwave energy, optical energy, focusedultrasound energy (e.g., high-intensity focused ultrasound energy),and/or another suitable type of energy. An electrode or transducer usedto deliver this energy can be used alone or with other electrodes ortransducers in a multi-electrode or multi-transducer array.

Neuromodulation using focused ultrasound energy (e.g., high-intensityfocused ultrasound energy) can be beneficial relative to neuromodulationusing other treatment modalities. Focused ultrasound is an example of atransducer-based treatment modality that can be delivered from outsidethe body. Focused ultrasound treatment can be performed in closeassociation with imaging (e.g., magnetic resonance, computed tomography,fluoroscopy, ultrasound (e.g., intravascular or intraluminal), opticalcoherence tomography, or another suitable imaging modality). Forexample, imaging can be used to identify an anatomical position of atreatment location (e.g., as a set of coordinates relative to areference point). The coordinates can then entered into a focusedultrasound device configured to change the power, angle, phase, or othersuitable parameters to generate an ultrasound focal zone at the locationcorresponding to the coordinates. The focal zone can be small enough tolocalize therapeutically-effective heating at the treatment locationwhile partially or fully avoiding potentially harmful disruption ofnearby structures. To generate the focal zone, the ultrasound device canbe configured to pass ultrasound energy through a lens, and/or theultrasound energy can be generated by a curved transducer or by multipletransducers in a phased array, which can be curved or straight.

Heating effects of electrode-based or transducer-based treatment caninclude ablation and/or non-ablative alteration or damage (e.g., viasustained heating and/or resistive heating). For example, a treatmentprocedure can include raising the temperature of target neural fibers toa target temperature above a first threshold to achieve non-ablativealteration, or above a second, higher threshold to achieve ablation. Thetarget temperature can be higher than about body temperature (e.g.,about 37° C.) but less than about 45° C. for non-ablative alteration,and the target temperature can be higher than about 45° C. for ablation.Heating tissue to a temperature between about body temperature and about45° C. can induce non-ablative alteration, for example, via moderateheating of target neural fibers or of luminal structures that perfusethe target neural fibers. In cases where luminal structures areaffected, the target neural fibers can be denied perfusion resulting innecrosis of the neural tissue. Heating tissue to a target temperaturehigher than about 45° C. (e.g., higher than about 60° C.) can induceablation, for example, via substantial heating of target neural fibersor of luminal structures that perfuse the target fibers. In somepatients, it can be desirable to heat tissue to temperatures that aresufficient to ablate the target neural fibers or the luminal structures,but that are less than about 90° C. (e.g., less than about 85° C., lessthan about 80° C., or less than about 75° C.).

Renal neuromodulation can include a chemical-based treatment modalityalone or in combination with another treatment modality. Neuromodulationusing chemical-based treatment can include delivering one or morechemicals (e.g., drugs or other agents) to tissue at or near a treatmentlocation in a manner that modulates neural function. The chemical, forexample, can be selected to affect the treatment location generally orto selectively affect some structures at the treatment location overother structures. The chemical, for example, can be guanethidine,ethanol, phenol, a neurotoxin, or another suitable agent selected toalter, damage, or disrupt nerves. A variety of suitable techniques canbe used to deliver chemicals to tissue at or near a treatment location.For example, chemicals can be delivered via one or more needlesoriginating outside the body or within the vasculature or other bodylumens. In an intravascular example, a catheter can be used tointravascularly position a treatment assembly including a plurality ofneedles (e.g., micro-needles) that can be retracted or otherwise blockedprior to deployment. In other embodiments, a chemical can be introducedinto tissue at or near a treatment location via simple diffusion througha body lumen wall, electrophoresis, or another suitable mechanism.Similar techniques can be used to introduce chemicals that are notconfigured to cause neuromodulation, but rather to facilitateneuromodulation via another treatment modality.

CONCLUSION

This disclosure is not intended to be exhaustive or to limit the presenttechnology to the precise forms disclosed herein. Although specificembodiments are disclosed herein for illustrative purposes, variousequivalent modifications are possible without deviating from the presenttechnology, as those of ordinary skill in the relevant art willrecognize. In some cases, well-known structures and functions have notbeen shown and/or described in detail to avoid unnecessarily obscuringthe description of the embodiments of the present technology. Althoughsteps of methods may be presented herein in a particular order, inalternative embodiments the steps may have another suitable order.Similarly, certain aspects of the present technology disclosed in thecontext of particular embodiments can be combined or eliminated in otherembodiments. Furthermore, while advantages associated with certainembodiments may have been disclosed in the context of those embodiments,other embodiments may also exhibit such advantages, and not allembodiments need necessarily exhibit such advantages or other advantagesdisclosed herein to fall within the scope of the present technology.Accordingly, this disclosure and associated technology can encompassother embodiments not expressly shown and/or described herein.

The methods disclosed herein include and encompass, in addition tomethods of practicing the present technology (e.g., methods of makingand using the disclosed devices and systems), methods of instructingothers to practice the present technology. For example, a method inaccordance with a particular embodiment includes intravascularlypositioning a catheter at a treatment site within a vessel of a humanpatient. The intravascular catheter can include an elongated tubularshaft extending along a longitudinal axis, a therapeutic assembly at adistal portion of the shaft, and a pair of electrodes carried by thetherapeutic assembly. A control member is operably coupled between thetherapeutic assembly and a handle at a proximal portion of the shaft andexternal to the patient. The method can further include slidably movingthe control member in a proximal or distal direction to transform thetherapeutic assembly between (a) a low-profile delivery arrangementwherein the pair of electrodes are in a staggered arrangement relativeto each other and the longitudinal axis, and (b) a deployed arrangementwherein the pair of electrodes lie in a plane orthogonal to thelongitudinal axis.

Throughout this disclosure, the singular terms “a,” “an,” and “the”include plural referents unless the context clearly indicates otherwise.Similarly, unless the word “or” is expressly limited to mean only asingle item exclusive from the other items in reference to a list of twoor more items, then the use of “or” in such a list is to be interpretedas including (a) any single item in the list, (b) all of the items inthe list, or (c) any combination of the items in the list. Additionally,the terms “comprising” and the like are used throughout this disclosureto mean including at least the recited feature(s) such that any greaternumber of the same feature(s) and/or one or more additional types offeatures are not precluded. Directional terms, such as “upper,” “lower,”“front,” “back,” “vertical,” and “horizontal,” may be used herein toexpress and clarify the relationship between various elements. It shouldbe understood that such terms do not denote absolute orientation.Reference herein to “one embodiment,” “an embodiment,” or similarformulations means that a particular feature, structure, operation, orcharacteristic described in connection with the embodiment can beincluded in at least one embodiment of the present technology. Thus, theappearances of such phrases or formulations herein are not necessarilyall referring to the same embodiment. Furthermore, various particularfeatures, structures, operations, or characteristics may be combined inany suitable manner in one or more embodiments of the presenttechnology.

We claim:
 1. A catheter apparatus comprising: an elongated tubular shaftextending along a longitudinal axis, wherein the elongated shaftincludes a proximal portion and a distal portion; and a treatmentassembly at the distal portion of the shaft and configured to be locatedat a target location within a blood vessel of a human patient, whereinthe treatment assembly comprises a basket assembly including (a) a firststrut carrying a first electrode, (b) a second strut carrying a secondelectrode, (c) a third strut carrying a third electrode, and (d) afourth strut carrying a fourth electrode, and further wherein: the firststrut includes a first fixed end coupled to the shaft and a first freeend slidably engaged with the shaft at a location distal of the firstfixed end; the second strut includes a second fixed end coupled to theshaft and a second free end slidably engaged with the shaft at alocation proximal of the second fixed end; the third strut includes athird fixed end coupled to the shaft and a third free end slidablyengaged with the shaft at a location distal of the third fixed end; andthe fourth strut includes a fourth fixed end coupled to the shaft and afourth free end slidably engaged with the shaft at a location proximalof the fourth fixed end, wherein when the treatment assembly is in alow-profile delivery configuration, the first, second, third, and fourthelectrodes are in a staggered arrangement relative to each other alongthe longitudinal axis, and when the treatment assembly is in a deployedconfiguration, the first and second electrodes are aligned along a firstelectrode axis orthogonal relative to the longitudinal axis, and thethird and fourth electrodes are aligned along a second electrode axisorthogonal relative to the longitudinal axis, wherein the first andsecond electrode axes are spaced apart along the longitudinal axis and90 degrees offset from each other.
 2. The catheter apparatus of claim 1wherein: the first and third fixed ends are aligned along thelongitudinal axis; the first and third free ends are aligned along thelongitudinal axis at a location distal of the first and third fixedends; the second and fourth fixed ends are aligned along thelongitudinal axis at a location between the first and third fixed endsand the first and third free ends; and the second and fourth free endsare aligned along the longitudinal axis at a location proximal of thefirst and third fixed ends.
 3. The catheter apparatus of claim 1,further comprising: a first control member operably coupled between (a)the first and third free ends and (b) a handle at the proximal portionof the shaft; and a second control member operably coupled between (c)the second and fourth free ends and (d) the handle, wherein the firstand second control members are configured to be actuated in oppositedirections to transform the treatment assembly between the low-profiledelivery configuration and the deployed configuration.
 4. The catheterapparatus of 11 wherein: the first control member comprises a push wireconfigured to slidably move the first and third free ends in a distaldirection to transform the first and third struts of the treatmentassembly between the delivery configuration and the deployedconfiguration; and the second control member comprises a pull wireconfigured to slidably move the second and fourth free ends in aproximal direction to transform the second and fourth struts of thetreatment assembly between the delivery configuration and the deployedconfiguration.
 5. The catheter apparatus of claim 1 wherein the shaftand the treatment assembly are configured to fit within a guide sheathor guide catheter having a 6 F outer diameter.
 6. The catheter apparatusof claim 1 wherein each electrode comprises at least one planar surface.7. The catheter apparatus of claim 1 wherein each electrode comprises acrescent-shaped cross-sectional profile.